In recent years there have been various attempts to develop touch sensors that can detect hover at further distances above the sensor surface. One approach is described in U.S. Patent Application No. 62/428,862 filed Dec. 1, 2016 and entitled Signal Injection to Enhance Appendage Detection and Characterization. According to that specification, the invention therein relates to touch and in-air sensitive input devices. That document describes the use of signal injection (a/k/a signal infusion) to enhance appendage detection. Further disclosures concerning hover-seeking technologies can be found in U.S. Provisional Patent Application No. 62/488,753 file Apr. 22, 2017 and entitled Heterogenous Sensing Apparatus and Method, which, among other things, disclosed certain infusion techniques for use on a handheld sensor. Subsequently further disclosures were made in U.S. Provisional Patent Application No. 62/588,267, filed Nov. 17, 2017 and entitled Sensing Controller.
Trying to understand and model the position of a hand with respect to a sensor presents several challenges. For example, in an infusion system, signal from nearby digits may be confused with signal from another digit. U.S. Provisional Patent Application No. 62/533,405, filed Jul. 17, 2017, entitled Apparatus and Methods for Enhancing Digit Separation and Reproduction described techniques for digit separation. While better methods of finger separation may be developed to use existing sensor data, what is needed is a sensor that can reduce interference from e.g., nearby digits. Additionally, determination of and accurate modeling finger and hand gestures, motions and poses are also desired.